Combination fan blade unit for electric fan

ABSTRACT

A combination fan blade unit includes a fan hub defining an installation chamber and an axle hole in the installation chamber, a plurality of blower blades radially equiangularly arranged on the top sidewall of the fan hub, and a plurality of axial-flow blades radially equiangularly arranged around the peripheral wall of the fan hub.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an electric fan and, morespecifically, to a combination fan, which produces a big amount of windwhen operated.

[0002] An axial-flow fan is generally comprised of a fan motor, and afan blade unit. The fan blade unit 12 comprises a fan hub 19, and aplurality of blades 18 equiangularly spaced around the periphery 20 ofthe fan hub 19 (see FIG. 2). The detailed axial-flow fan structure 10,as shown in FIG. 1, comprises a housing 11, a fan blade unit 12, acircuit board 13, a coil 14, a permanent magnet 15, an axle bearing 16,and a shaft 17. When connecting electricity to the coil 14, an electricmagnetic field is produced and acted with the magnetic field of thepermanent magnet 15, causing electric energy to be turned into dynamicenergy to rotate the fan unit 12. Because this structure of axial-flowfan is of the known art, no further detailed description is necessary.

[0003] Conventional axial-flow fans are commonly used for coolingcomputers CPU and AC adapter and other industrial products. In order toimprove cooling and heat dissipation efficiency, the most direct andeffective way is to increase the amount of wind. Increasing the amountof wind can be achieved by different measures, for example, increasingthe revolving speed of the fan motor or changing the design of the fanblade unit.

[0004] Increasing the revolving speed of the fan motor relativelyincreases the amount of wind, therefore the cooling and heat dissipationeffective is relatively improved. However, increasing the revolvingspeed of the fan motor causes the axle bearing to wear quickly. The heatproduced due to friction between the shaft and the axle bearing causesthe axle bearing to be damaged quickly, resulting in short service lifeof the axial-flow fan. Keeping the fan blade in balance is anotherimportant factor to be taken into account when wishing to increase theamount of wind by increasing the revolving speed of the fan motor. Ifthe blades of the fan blade unit are not arranged in balance, the bladeswill vibrate when starting the axial-flow fan, affecting the axial-flowfan quality and its service life. Therefore, it is not a good measure toincrease the amount of wind simply by increasing the revolving speed ofthe fan motor. Further, increasing the revolving speed of the fan motoralso results in waste of power and increase of heat. Therefore, the bestway to increase the amount of wind is to change the design of the fanblade unit.

SUMMARY OF THE INVENTION

[0005] The present invention has been accomplished under thecircumstances in view. It is one object of the present invention toprovide a combination fan blade unit for electric fan, which produces abig amount of wind to achieve a high cooling and heat dissipationeffect.

[0006] It is another object of the present invention to provide acombination fan blade unit for electric fan, which reduces wearing ofthe axle bearing of the fan and the production of heat during theoperation of the fan.

[0007] According to one embodiment of the present invention, thecombination fan blade unit comprises a fan hub defining an installationchamber and an axle hole in the installation chamber, a plurality ofblower blades radially equiangularly arranged on the top sidewall of thefan hub, and a plurality of axial-flow blades radially equiangularlyarranged around the peripheral wall of the fan hub.

[0008] According to another embodiment of the present invention, thecombination fan blade unit comprises a fan hub defining an installationchamber and an axle hole in the installation chamber, a plurality ofblower blades radially equiangularly arranged on the top sidewall of thefan hub, and two sets of axial-flow blades alternatively arranged aroundthe peripheral wall of the fan hub at different elevations.

BRIEF DESCRIPTIONN OF THE DRAWINGS

[0009]FIG. 1 is a sectional view of an axial-flow fan according to theprior art.

[0010]FIG. 2 is an elevational view of a fan blade unit for anaxial-flow fan according to the prior art.

[0011]FIG. 3 is an oblique elevation of a fan blade unit for anaxial-flow fan according to the present invention.

[0012]FIG. 4 is a top view of the fan blade unit according to thepresent invention.

[0013]FIG. 5 is a longitudinal view in section of the fan blade unitaccording to the present invention.

[0014]FIG. 6 is a sectional view showing the fan blade unit installed inan axial-flow fan according to the present invention.

[0015]FIG. 7 is an oblique elevation of an alternate form of the fanblade unit according to the present invention.

[0016]FIG. 8 is a top view of the fan blade unit shown in FIG. 7.

[0017]FIG. 9 is a longitudinal view in section of the fan blade unitshown in FIG. 7.

[0018]FIG. 10 is a sectional view showing the fan blade unit of FIG. 7installed in an axial-flow fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] Referring to FIGS. from 3 through 6, a combination fan blade unit32 is shown comprising a fan hub 39. The fan hub 39 comprises a circulartop wall 40, and a peripheral wall 41 downwardly extended from theborder of the circular top wall 40. The top wall 40 and the peripheralwall 41 define an installation chamber 42 adapted to receive thecomponent parts of an axial-flow fan 30 including a permanent magnet 35,a coil 34, and a circuit board 33 (see FIG. 6, the reference sign 31indicates a housing). The installation chamber 42 comprises an axle hole43, which receives one end of the shaft, referenced by 37. The other endof the shaft 37 is inserted through an axle bearing 36 to supportrotation of the fan blade unit 32. Blower blades 44 are radiallyequiangularly arranged on the top wall 40 of the fan hub 39. Axial-flowblades 45 are radially equiangularly arranged around the peripheral wall41 of the fan hub 39. During rotary motion of the fan unit 32 in theaxial-flow fan 30, the blower blades 44 draw currents of air from thetopside vertically downwardly toward the axial-flow blades 45, enablingthe axial-flow blades 45 to send out currents of air. By means of theaction of the blower blades 44 and the axial-flow blades 45, a bigamount of wind is produced to achieve a high cooling and heatdissipation effect without producing much noise and heat. Therefore, incomparison with prior art designs, the revolving speed of the motor canbe relatively reduced to achieve same output.

[0020] FIGS. from 7 through 9 show an alternate form of the presentinvention. According to this alternate form, the fan blade unit 52comprises a fan hub 59. The fan hub 59 comprises a circular top wall 60,and a peripheral wall 61 downwardly extended from the border of thecircular top wall 60. The top wall 60 and the peripheral wall 61 definean installation chamber 62 adapted to receive the component parts of anaxial-flow fan 50 including a permanent magnet 55, a coil 54, and acircuit board 53 (see FIG. 10, the reference sign 51 indicates ahousing). The installation chamber 62 comprises an axle hole 63, whichreceives one end of the shaft, referenced by 57. The other end of theshaft 57 is inserted through an axle bearing 56 to support rotation ofthe fan blade unit 52. Further, two sets of axial-flow blades 64 and 65are alternatively arranged around the peripheral wall 61 of the fan hub59 at different elevations. This alternate form achieves the followingadvantages:

[0021] 1. Increasing the number of blades in a limited space;

[0022] 2. Increasing the number of wind-cut holes 66 and wind outlets 67so as to increase the amount of wind and improve the cooling and heatdissipation effect; and

[0023] 3. Increasing the wind pressure without changing the wind outputangle and the position of the wind outlets.

[0024] As indicated above, the fan blade units 32 and 52 achieve theeffect of producing a big amount of wind, enabling the axial-flow fans30 and 50 to provide sufficient amount of wind for cooling and heatdissipation purpose without increasing the revolving speed of the fanmotor. With respect axle bearing service life, it is calculated subjectto JIS as follows:$L = {\frac{10}{60N}\left( \frac{c}{p} \right)({hr})}$

[0025] in which, N=revolving speed (RPM: Revolution Per Minute);

[0026] C=development rated load (Kgf);

[0027] P=load at axle bearing (Kgf).

[0028] According to the aforesaid equation, when the conditions of P andC remained unchanged, the service life of the axle bearing (fan) isindirectly proportional to the revolving speed. Because the inventioncan produce same amount of wind at a relatively lower revolving speed,less friction is produced between the shaft and the axle bearing andless noise and heat is produced during the operation of the fanaccording to the present invention. Therefore, the invention greatlyextends the service life of the fan.

[0029] It is to be understood that the drawings are designed forpurposes of illustration only, and are not intended for use as adefinition of the limits and scope of the invention disclosed. Forexample, blower blades may be radially equiangularly provided at thecircular top wall 60 of the fan blade unit 52 of the embodiment shown inFIG. 7.

What the invention claimed is:
 1. A combination fan blade unitcomprising a fan hub, said fan hub comprising a circular top wall, and aperipheral wall extended from the border of said circular top wall anddefining with said circular top wall an installation chamber and an axlehole in said installation chamber, a plurality of blower blades radiallyequiangularly arranged on said circular top wall, and a plurality ofaxial-flow blades radially equiangularly arranged around said peripheralwall of said fan hub.
 2. A combination fan blade unit comprising a fanhub, said fan hub comprising a circular top wall, and a peripheral wallextended from the border of said circular top wall and defining withsaid circular top wall an installation chamber and an axle hole in saidinstallation chamber, and two sets of axial-flow blades alternativelyarranged around said peripheral wall of said fan hub at differentelevations.
 3. The combination fan blade unit of claim 2 furthercomprising a plurality of blower blades radially equiangularly arrangedon said circular top wall.